Neutralizing layer for color diffusion transfer film

ABSTRACT

Novel photographic products for use in diffusion transfer systems for forming visible images, particularly systems for forming color images viewable, without separation as color reflection prints, which products include a neutralizing layer for lowering the environmental pH after application of an aqueous alkaline processing fluid, the neutralizing layer comprising a graft copolymer of an acid moiety grafted onto a polymeric backbone.

United States Patent [191 [111 3,765,885 Bedell Oct. 16, 1973 [54] NEUTRALIZING LAYER FOR COLOR 3,384,483 5/1968 Becker 96/3 3,579,333 5/1971 Land et al.. DIFFUSION TRANSFER FILM 3,647,434 3/1972 Land 96/29 D [75] Inventor: Stanley F. Bedell, Andover, Mass.

[73] Assignee: Polaroid Corporation, Cambridge, Primary Examiner-N9rman Torcfhin Mass. Assistant Examiner-Richard L. SChlllll'lg Attorney-Alvin Isaacs [22] Filed: Jan. 3, 1972 [21] Appl. N0.: 214,746 [57] ABSTRACT Novel photographic products for use in diffusion [52 us. Cl 96/3, 96/77, 96/119 transfer system for forming visible images, P

['58] Field of Search 96/77, 3, 29 D out Separation as color fl ti n prints, which products include a neutralizing layer for lowering the envi- [56] References Cited ronmental pH after application of an aqueous alkaline UNITED STATES PATENTS processing fluid, the neutrallz tmg layer compnsmg a graft copolymer of an acld molety grafted onto a poly- 3,362,821 1/1968 Land 96/3 meric backbone 3,415,644 12/1968 Land 96/29 D 3,689,262 9/1972 Rogers 96/29 D 19 Claims, 1 DrawingFigure V /}r/SUPPORT I3 Q/CYAN DYE DEVELOPER LAYER RED-SENSITIVE SILVER HALIDE EMULSION LAYER |5- larly systems for forming color images viewable, with- /-INTERLAYER IVMAGENTA' DYE DEVELOPER LAYER GREEN-SENSITIVE SILVER HALIDE EMULSION LAYER I -YELLOW DYE DEVELOPER LAYER ELU E- SENSITIVE I SILVER HA LIDE MU LSION LAYER I AUXILIARY LAYER IMAGERECEIVING LAYER SPACER LAYER I SUPPORT PAHNIFnncHsms 3.765.885

{SUPPORT /CYAN DYE DEVELOPER LAYER RED-SENSITIVE SILVER HALIDE EMULSION LAYER INTERLAYER MAGENTA DYE [IVELOPER LAYER L. GREEN-SENSITIVE SILVER HALIDE I EMULSION LAYER f INTERLAYER YELLQW DYE DEVELOPER LAYER BLUE-SENSITIVE SILVER HALIDE EMULSION LAYER P AUXILIARY LAYER IMAGERECEIVING LAYER SPACER LAYER A/NEUTRALIZING LAYER 25 d SUPPORT NEUTRALIZING LAYER FOR COLOR DIFFUSION TRANSFER FILM BACKGROUND OF THE INVENTION Various diffusion transfer systems for forming color images have heretofore been disclosed in the art. Generally speaking, such systems rely for color image formation upon a differential in mobility or solubility of a dye image-providing material obtained as a function of development so as to provide an imagewise distribution of such material which is more diffusible and which is therefore selectively transferred, at least in part, by diffusion, to a superposed dyeable stratum to impart thereto the desired color transfer image. The differential in mobility or solubility may for example be obtained by a chemical action such as a redox reaction or a coupling reaction.

The dye image-providing materials which may be em ployed in such processes generally may be characterized as either (I) initially soluble or diffusible in the processing composition .but are selectively rendered non-diffusible in an imagewise pattern as a function of development; or (2) initially insoluble or non-diffusible in the processing composition but which are selectively rendered diffusible in an imagewise pattern as a func- .tion of development. These materials may be complete dyes or dye intermediates, e.g., color couplers.

As examples of initially soluble or diffusible materials and their application in color diffusion transfer, mention may be made of those disclosed, for example, in U. S. Pat. Nos. 2,647,049; 2,661,293; 2,698,244; 2,698,798; 2,802,735; 2,774,668; and 2,983,606. As examples of initially non-diffusible materials and their use in color transfer systems, mention may be made of the materials and systems disclosed in U. S. Pat. Nos. 3,443,939; 3,443,940; 3,227,550; 3,227,552; 3,227,554; 3,243,294 and 3,445,228.

In any of these systems, multicolor images are obtained by employing a film unit containing at least two selectively sensitized silver halide layers each having associated therewith a dye image-providing material exhibiting desired spectral absorption characteristics. The most commonly employed elements of this type are the so-called tripack structures employing a blue-, a greenand ared-sensitive silver halide layer having associated therewith, respectively, a yellow, a magenta and a cyan dye image-providing material.

A particularly useful system for forming color images by diffusion transfer is that described in U. S. Pat. 'No.

2,983,606, employing dye developers (dyes which are also silver halide developing agents) as the dye imageproviding materials. In such systems, a photosensitive element comprising at least one silver halide layer having a dye developer associated therewith (in the same or in an adjacent layer) is developed by applying an aqueous alkaline processing composition. Exposedand developable silver halide is developed by the dye developer which in turn becomes oxidized to provide an oxidation product which is appreciably less diffusible-than the unreacted dye developer, thereby providing an imagewise distribution of diffusible dye developer in terms of unexposed areas of the silver jalide halide which imagewise distribution is then transferred, at least in part, by diffusion, to a dyeable stratum to impart thereto a positive dye transfer image. Multicolor images may be obtained with a photosensitive element having two or more selectively sensitized silver halide layers and associated dye developers, a tripack structure of the type described above and in various patents including the aforementioned U. S. Pat. No. 2,983,606 being especially suitable for accurate color recordation of the original subject matter.

In color diffusion transfer systems of the foregoing description, color images are obtained by exposing a photosensitive element or negative component comprising at least a light-sensitive layer, e.g., a gelatino silver halide emulsion layer, having a dye imageproviding material associated therewith in the same or in an adjacent layer, to form a developable image developing this exposed element with a'processing composition to form an imagewise distribution of a soluble and diffusible image-providing material; and transferring this imagewise distribution, at least in part, by diffusion, to a superposed receiving element or positive component comprising at least a dyeable stratum to impart to this stratum a color transfer image. The negative and positive components may be separate elements which are brought together during processing and thereafter either retained together as the final print or separated following image formation; or they may together comprise a unitary structure, e.g., integral negative-positive film units wherein the negative and positive components are laminated and/or otherwise physically retained together at least prior to image formation.

While the present invention is applicable both to those systems wherein the dyeable stratum is contained on a separate element and to those systems wherein the dyeable stratum and the photosensitive stratacomprise a unitary structure, of particular interest are those integral negative-positive film units adapted for forming color transfer images viewable without separation, i.e.,

wherein the positive component need not be separated gether in physical juxtapostion as a single structure. I

Film units intended to provide multicolor images comprise two or more selectively sensitized silver halide layers each having associated therewith an appropriate dye image-providing material exhibiting desired spectral absorptioncharacteristics. As was heretofore men-' tioned the most commonly employed negative components for forming multicolor images are of the tripack structure containing a blue-, a greenand a redsensitive silver halide layer having associated therewith in the same or in a contiguous layer a yellow, a magenta and acyan dye image-providng material respectively. Interlayersor spacer layers may if desired be provided between the respective silver halide layers and associated dye image-providing materials. In addition to the aforementioned essential layers, such film units further include means for providing a reflecting layer between the dyeable stratum and the negative component in order to mask effectively the silver image or images formed as a function of development of the silver halide layer or layers and any remaining associated dye image-providing material and to provide a background for viewing the color image formed in the dyeable stratum, without separation, by reflected light. This reflecting layer may comprise a preformed layer of a reflecting agent included in the essential layers of the film unit or the reflecting agent may be provided after photoexposure, e.g., by including the reflecting agent in the processing composition. These essential layers are preferably contained on a transparent dimensionally stable layer or support member positioned closest to the dyeable stratum so that the resulting transfer image is viewable through this transparent layer. Most preferably another dimensionally stable layer which may be transparent or opaque is positioned on the opposed surface of the essential layers so that the aforementioned essential layers are sandwiched or confined between a pair of dimensionally stable layers or supportmembers, at least one of each is transparent to permit viewing therethrough of a color transfer image obtained as a function of development of the exposed film unit in accordance with the known color diffusion transfer system such as will be detailed hereinafter. In a particularly preferred form such film units are employed in conjunction with a rupturable container of known description containing the requisite processing composition and adapted upon application of pressure of applying its contents to develop the exposed film unit, e.g., by applying the processing composition in a substantially uniform layer between the dyeable stratum and the negative component. It will be appreciated that the film unit may optionally contain other layers performing specific'desired functions, e.g., spacer layers, etc.

Opacifying means may be provided on either side of the negative component so that the film unit may be processed in the light to provide the desired color transfer image. In a particularly useful embodiment such opacifying means comprise an opaque dimensionally stable layer or support member positioned on the free or outer surface of the negative component, i.e., on the surface of the film unit opposed from the positive component containing the dyeable stratum 'to prevent photoexposure by actinic light incident thereon from this side of the film unit and an opacifying agent applied during development between the dyeable stratum and the negative component, e.g., by including the opacifying agent in a developing composition so applied, in order to prevent further exposure (fogging) by actinic light incident thereon from the other side of the fllm unit when the thus exposed film unit is, developed in the light. The last-mentioned opacifying agent may comprise the aforementioned reflecting agent which masks the negative component and provides the -requi-.

site background for viewing the transfer image formed thereover. Where this reflecting agent does not by itself 4 appropriate processing composition to develop exposed silver halide and to form, as a function of development, an imagewise distribution of diffusible dye image-providing material which is transferred, at least in part by diffusion, to the dyeable stratum to impart thereto the desired color transfer image, e.g., a positive color transfer image. Common to all of these systems in the provision of a reflecting layer between the dyeable stratum and the photosensitive strata to mask effectively the latter and to provide a background for viewing the color image contained in the dyeable stratum, whereby this image is viewable without separation, from the other layers or elements of the film unit. In certain of these systems, this reflecting layer is provided' prior to photo-exposure, e.g., as a preformed layer included in the essential layers of the laminar structure comprising the film unit, and in others it is provided at some time thereafter, e.g., by including a suitable light-reflecting agent, for example, a white pigment such as titanium dioxide, in the processing composition which is applied between thp dyeable stratum and the next adjacent layer to develop the latent image and to form the color transfer image.

The dyeimage-providing materials which may be employed in such processes generally are selected from those materials heretofore mentioned and disclosed in the illustrative patents which were initially soluble or diffusible in the processing composition but which are selectively rendered non-diffusible as a function of development or those which are initiallyinsoluble or nondiffusible in the processing composition but are selectively rendered diffusible as a function of development. These materials may be complete dyes or dye intermediates, e.g., color couplers.

A preferred opacification system to be contained in the processing composition is that described in the copending applications of Edwin H. Land, Ser. No. 43,782, filed June 5, 1970 now U.S. Pat. No. 3,647,437 and Ser. No. 101,968, filed Dec. 28, 1970, comprising an inorganic reflecting pigment dispersion containing at least one optical filter agent at a pH abovethe pKa of the optical filter agent in a concentration effective, when the processing composition is applied, to provide provide the requisite opacity it may be employed in combination with an additional opacifying agent in order to prevent further exposure of the light-sensitive silver halide layer or layers by actinic light incident thereon.

As examples of such integral negative-positive film units for preparing color transfer images viewable without separation as reflection prints, mentioned may be made of those described and claimed in U. S. Pat. Nos.

about 6.0 density units with respect to incident radiation actinic to the photosensitive silver halide layer and optical reflection density than about 1.0 density with respect to incident visible radiation.

.In lieu of having the reflecting pigment contained in the processing composition, e.g., as disclosed in the aforementioned copending applications, the reflecting pigment needed to mask the photosensitive strata and to provide the requisite background for viewing the color transfer image formed in the receiving layer may be contained initially in whole or in part as a preformed layer in the film unit. As an example of such a preformed layer, mention may be made of that disclosed on the copending applications of Edwin H. Land, Ser.

Nos. 846,441, filed July 31, 1969 now U.S. Pat. No.

3,615,421, and 3,645, filed Jan. 19, 1970. now U. S. Pat. No. 3,615,421. The reflecting pigment may be generated in situ as is disclosed in the copending applications of Edwin E. Land, Ser. Nos. 43,741 and 43,742, both filed June 5, 1970 now U.S. Pat. Nos. 3,647,434 and 3,647,435 respectively.

In the various color diffusion transfer systems which have previously been described and which employ an aqueous alkaline processing fluid, it is well known to ample, U. S. Pat. No. 3,362,819 discloses systems wherein the desired pH reduction may be effected by providing a polymeric acid layer adjacent the dyeable stratum. These polymeric acids may be polymers which contain acid groups, e.g., carboxylic acid and sulfonic acid groups, which are capable of forming salts with alkali metals or with organic bases; or potentially acidyielding groups such as anhydrides or lactones. Preferably the acid polymer contains free carboxyl groups. An inert interlayer or spacer layer may be disposed between the polymeric acid layer and the dyeable stratum in order to control the pH reduction so that it is not premature and hence interferes with the development process, e.g., to time control the pH reduction. Suitable spacer or timer layers for this purpose are de-' scribed with particularity in this patent and in others, including U. S. Pat. Nos. 3,419,389, 3,421,893; 3,433,633; 3,455,686; and 3,575,701.

The copending application of Schlein et al., Ser. No. 165,171, filed July 22, 1971, describes and claims an acid layer comprising a water-soluble acid and a watersoluble binder in film units such as those previously de scribed and including a negative component comprising at least one light-sensitive silver halide layer and an associated dye image-providing material and a positive component containing a dyeable stratum. As is disclosed in this copending application, the use of such water-soluble ingredients in the neutralizing layer affords many distinct advantages over systems employing water-insoluble components which need be coated from an organic solvent. Apart from the readily apparent coating advantages in avoiding the use of organic solvents, is that it permits the use of shorter acid molecules with lower equivalent weights, which in turn permits one to employ thinner coatings, an important advantage in the film units to which the copending application is directed.

While the acid layer is preferably contained in the receiving element employed in systems wherein the dyeable stratum and photosensitive strata are contained on -separate elements, e.g., between the support for the receiving element and the dyeable stratum; or associated with the dyeable stratum in those integral film units, e.g., on the side of the dyeable stratum opposed from the negative component, the acid layer may, if desired, be disposed in a layer associated with the photosensitive strata, as is disclosed, for example, in U. S. Pat. Nos. 3,362,821 and 3,573,043.

U. S. Pat. No. 3,576,625 discloses integral film units containing yet another neutralizing system for lowering the pH. In accordance with that disclosure, the film unit is constructed to contain at least one layer containing a particulate dispersion of acid material. In general, this acid material may comprise any photographically nondeleterious acid material in solid or liquid state encapsulated within a polymeric wall material which is permeable to the alkaline processing composition.

The present invention is directed to another type of neutralizing material for lowering the environmental pH in color diffusion transfer systems of the type previously described, which material provides the distinct advantages and beneficial results which will be described hereinafter in the detailed description of the invention.

SUMMARY OF THE INVENTION In accordance with the present invention, a layer of a graph copolymer comprising an acid moiety grafted onto a polymeric backbone is employed to lower the pH. These graft copolymers are coated as aqueous emulsions, e.g., in. an aqueous medium, to provide a neutralizing layer which is characterized as being hydrophobic and possessing an extremely high peal force so as to be extremely adherent against separation or delamination from the contiguous layers of the photographic product in which it is employed.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE is an enlarged, fragmentary, diagrammatic, sectional view of a film unit contemplated by this invention.

DESCRIPTION OF PREFERRED EMBODIMENT In the preferred embodiment, the film unit is a socalled integral negative-positive tripack and the positive component includes the neutralizing layer of this invention in addition to the dyeable stratum. More preferably a timing or spacer layer of known description is disposed between the dyeable stratum and neutralizing layer, the preferred such timing layer being a polyvinylamide graft copolymer of the type described and claimed in U. S. Pat. No. 3,575,701 of Lloyd D. Taylor As was heretofore mentioned, the novel neutralizing layers of this invention are graft copolymers. They may be defined as being monomeric or polymeric acid moieties grafted onto a polymeric backbone comprising repeating units comprising structural units capable of being oxidized by a transition metal ion catalyst of a first oxidation state, the catalyst having an oxidation potential, in acidic solution of at least about 1 volt when the transition metal is reduced to the next lowest acidic solution stable oxidation state.

With regard to the backbone polymer of these graft polymers, generally speaking any organic polymer or copolymer containing repeating units comprising structural units including the grouping, wherein Y- is hydroxyl, carboxyl, amino, merpolyaldehydes, polyamides, cellulose, substituted celluloses such as methyl cellulose, hydroxycthel cellulose, methyl hydroxypropyl cellulose, starch, copolymers of ethylene and acids such as maleic acid, polymeric acids such as polyacrylic acid, etc.

The acid moiety grafted onto this polymeric backbone may be selected from a long list of useful acids, preferred acids being acrylic acid, homologues thereof such as methacrylic acid, esters thereof such as methyl acrylate, ethyl acrylate, and polymers and copolymers including the same.

As examples of useful monomers and polymers for the acid moiety, mention may be made of ethyl acrylate-acrylic acid copolymer, acrylic acid, isobutyl vinyl ether/maleic acid copolymer, vinyl acetate/acrylic acid copolymer, ethyl acrylate/methacrylic acid copolymer, methyl acrylate/acrylic acid copolymer, ethyl acrylate/acrylic acid/2-hydroxy-3- methylacrylyloxypropyl-trimethylammonium chloride terpolymer, methyl acrylate, diacetone acrylamide/acrylic acid copolymer, diacetone acrylamidie/acrylic acid/2-sulfoethyl methacrylate terpolymer, diacetone acrylamide/acrylic acid/sodium 2-sulfoethyl methacrylate terpolymer, ethyl acrylate/methacrylic acid/acrylic acid terpolymer, methyl acrylate/methacrylic acid copolymer, methyl acrylate/ethyl acrylate/methacrylic acid terpolymer, ethyl acrylate/methacrylic acid/diacetone acrylamide terpolymer, ethyl ethyl acrylate/acrylic acid/2-sulfoethyl methacrylate terpolymer, methyl acrylate/acrylic acidIZ-sulfoethyl methacrylate terpolymer, ethyl acrylate/methacrylic acid/sodium 2- sulfoethyl methacrylate terpolymer, methyl acrylate/- methacrylic acid/sodium 2-sulfoethy1 methacrylate terpolymer, methyl acrylate/methacrylic acid/sodium 2- sulfoethyl methacrylate/methylolated diacetone acrylamide tetrapolymer, diacetone acrylamide, diacetone acrylamide/butyl acrylate copolymer, butyl acrylate,

methyl acrylate/2-acrylamido-2-methyl-propane su1-.

fonic acid copolymer, methyl acrylatelZ-acrylamido-Z- methyl-propane sulfonic acid copolymer, diacetone acrylamide/Z-acrylamido-2-methyl-propane sulfonic acid copolymer, diacetone acrylamide/2-acrylamido-2 -methylpropane sulfonic acid/2-hydroxy-3-methacryloyloxypropyl trimethyl ammonium chloride terpolymer, diacetone acrylamide/butyl acrylate/2- acrylamido-Z-methyl-propane sulfonic acid/Z-hydroxy- 3-methacryloyloxypropyl trimethyl ammonium chloride tetrapolymer, butyl acrylate/2-acrylamido-2- methyl-propane sulfonic acid copolymer, etc.

As examples of useful graft polymers contemplated by this invention, mention may be made of the followmg:

OOCaHy, OOH

Ethyl acrylate afiiiidg'rar't on pBiyiiiii'yi alcohol (PVA). EAzAA 1:1; monomer:PVA 2:1.

2. Ethyl acrylate acrylic acid graft on PVA. EAzAA 1:1; monomer:PVA 4:1.

3. Ethyl acrylate acrylic acid graft on PVA. EA:AA 2:1; monomer:PVA 4:1.

4. Ethyl acrylate acrylic acid graft on PVA. EAzAA 1:1; monomer:PVA 1:1.

5. Ethyl acrylate acrylic acid graft on PVA. EAzAA 1:2; monomer:PVA 1.511.

6. Ethyl acrylate acrylic acid graft on PVA. EAzAA 1:2; monomer:PVA 0.75:1.

(7) CH -C Acrylic acid graft on PVA. PVAzmonomer 1:1.

CHz-Cl OH-CH:CH3

B &

H (CH,-- H). [OH- GH OOH OOH 1 lsoh u tyl m ma/male "ma" graft on PVA.

IVEzMA 1.1; PVA:monomer 1:1.

9. Vinyl acetate acrylic acid graft on PVA. VAzAA 2.3:1; monomer:PVA 0.83:1.

10. Vinyl acetate acrylic acid graft on PVA. VAzAA =1.2:1;monomer:PVA 1.1:1.

Ethyl acrylate methacrylic acid graft on PVA. EA:-

MAA 1:1; monomer:PVA 1:1.

(12) (IsopA A) 1 Ethyl acrylate acrylic acid on an isopr opyl acrylamide graft on PVA. lsopAAzEAzAA 1:1:1; monomer:-- PVA 3:1.

Methyl tzgaa ra iie 'aia' ari OHFVKI MAEXA 4.221; monomer:PVA 1.4:].

14. Methyl acrylate acrylic acid, graft MA:AA 2.1:1; monomer:PVA 1.7:1.

on PVA.

MA:AA 1:2.2; monomer:PVA 0.92:1.

' Fhyl"acrylatej acrylic acid and 2-hydroxy 3-nietliacryloyloxypropyl -trimethy1ammonium chloride (MTC) graft on PVA. EA:AA:MTC 25:25:1; monomerzPVA 1:1.

Ethyl acrylate, acrylic acid and 2-hydroxy-3-metha 5 cryloyloxypropyl -'trimethylammonium chloride (MTC) graft on PVA. EA:AAzMTC =6.3:1.8:1; monomer2PVA 0.7221.

Methyl acrylate, acrylic acid and 2-hydroxy-3-methacryloyloxypropyl -trimethylammonium chloride (MTC) graft on PVA. MA:AA:MTC 15:25:1; monomerzPVA 3:1.

23. Methyl acrylate, acrylic acid and 2-hydroxy-3- methacryloyloxypropyl -trimethylammonium chloride (MTC) graft on PVA. MAzAAzMTC 7.5:12.5:1; monomerzPVA 1.6621.

24. Methyl acrylate, acrylic acid and 2-hydroxy-3- methacryloyloxypropyl -trimethylammonium chloride (MTC) graft on PVA. MA:AA2MTC 521021; monomerzPVA 0.8121.

Methyl acrylate graft on PVA.

oal-c (26) cnf-c Diacetone acrylamide acrylicacid graft on PVA. DAAzAAzSEM 35:41:12moi1omer2PVA 4.621.-

27. Diacetone acrylamide acrylic acid graft o PVA. DAA:AA 5:4.

sulfoethyl methacrylate (NaSEM) graft on PVA. DAA- :AAzNaSEM 5329221; monomerzPvA 5.8:]; i

Ethyl acrylate methacrylic acid acrylic acid graft on hydroxyethyl cellulose (HEC). EA2MAA2AA 2.5:4.5:1;monomer:l-1EC 3.311 (by wt.)

30. Ethyl acrylate methacrylic acid acrylic acid graft on HEC. EAzMAAzAA 1.7:321; mOnomer2HEC 3.521 (by wt.)

31. Ethyl acrylate methacrylic acid graft on HEC. EA2MAA 121.7; monomer2l-1EC 3:1 (by wt.)'

32. Ethyl acrylate methacrylic acid'graft on HEC. EAzMAA 122.3; monomer2HEC 3.521 (by wt.)

33. Methyl acrylate methacrylic acid graft on HEC. MAzMAA 2:3.

34. Methyl acrylate methacrylic acid graft on HEC. MAzMAA 1:2; monomer:HEC 3.521 (by wt.)

35. Methyl acrylate acrylic acid graft on HEC. MAzAA 1:2; monomerzHEC 3:1 (by wt.)

- 36. Methyl acrylate acrylic acid graft on HEC. MA2AA 1:1.

37. Methyl acrylate methacrylic acid 2-sulfoethylmethacrylate graft on HEC. MAzMAAzSEM 42:63: 1; monome'r2l-1EC 3:1 (by wt.)

38. Methyl acrylate ethyl acrylate methacrylic acid graft on HEC. MA:EA:MAA 4:1:8; monomercHEC =321 (by wt.) I

Ethyl acrylate methacrylic acid diacetone acrylamide graft on HEC. EAzMAAzDAA l2:21:1;monomerzHEC 3.221 (by wt.)

40. Ethyl acrylate. methacrylic acid diacetone acrylamide graft on HEC. EAzMAAzDAA 12221:2; monomer2HEC 3.3:1 (by wt.)

( (starch) (EA) (AA) starch.

on starch.

on starch.

on starch.

on starch.

. )1(MAA) Methyl acrylate methacrylic acid graft on starch. MA:MAA"= 1:1.5; starchzmonomer 123 (by wt.)

(49) lifiiN mwwwn Ethyl acrylate acrylic acid 2-sulfoethyl methacrylate (SEM) graft on. starch. EA:AAzSEM 2426221; starch2monomer 121.5 (by wt.)

50. Ethyl acrylate acrylic acid 2-sulfoethyl methacrylate (SEM)' graft on starch. EA:AAzSEM 62:188z1; starch2monomer 121.7 (by wt.)

Methyl acrylate acrylic acid 2-sulfoethy1 methacrylate graft on starch. MA:AA:SEM 84:15021; starch: monomer 1:3 (by wt.)

starch.

(starch Methyl acrylate methacrylic acid sodium 2- sulfoethyl methacrylate graft on starch. MA:MAA:- NaSEM 972146;]; starchzmonomer 1:3 (by wt.)

Ethyl acrylate methacrylic acid sodium 2- sulfoethyl methacrylate graft on starch. EA:MAA:- NaSEM 28:48:1; starchzmonomer 1:3 (by -wt.)

54 t h i \KHMPAM(NBSEMXIMXMAM.

' -Methy1 acrylate methacrylic acid sodium 2- sulfoethyl methacrylate methylolated diacetone acrylamide graft on starch. HMDAAzNaSEMzMAzMAA 1221;97:146; starchzmonomer 1:3 (by wt.)

55 t 11 (We MA S.(MAA)1M EM I Methylacrylate methacrylic acid 2-sulfoethyl methacrylate graft on starch. MA:MAA: SEM 8421461; starchzmonomer 1:3 (by wt.)

Ethyl acrylate acrylic acid 2-sulfoethyl methacrylate graft on starch. EAzAAzSEM 72:150z1; starch- :monomer 1:3 (by wt.)

CH7CHa-CH-C L OOH (soon (MAXAMPS) Methyl acrylate 2-acrylamido-2-methyl-propane V sulfonic acid (AMPS) graft on ethylene/maleic acid copolyrner. MAzAMPS 46:1; monomerzEMA 121.5.

l. 0915! c 11 (DAAXAMPfi) Diacetone acrylamide 2-acrylamido-2-rnethylpropane sulfonic acid graft on ethylene/maleic acid copolymer. DAA:AM PS 24:1; monomerzEMA 12 2.8.

C l L 12 propyl trimethyl ammonium chloride (HMTAC) on ethylene/maleic acid copolymer. DAAzAMPSzH- MTAC 38:1:1; monomerzEMA 111.1.

60. Diacetone acrylamide butyl acrylate 2-acrylamido-2-methyl-propane sulfonic acid 2- hydroxy-3-methacryloyloxypropyl trimethyl ammonium chloride graft on ethylene/maleic acid copolymer.DAA:BA:AMPS:l-1MTAC 24:20:1:1; monomer- :EMA 1:096.

61. Butyl acrylate 2-acrylamido-2-methyl-propane sulfonic acid graft on ethylenelmaleic acid copolymer.

62. ..Methyl acrylate Z-acrylamido-2-methylpropane sulfonic acid (AMPS) graft on polyacrylic acid.

63. Diacetone acrylamide 2-acrylamido-2-methylpropane sulfonic acid graft on polyacrylic acid.

Diacetore acrylamide 2-acrylamido-2-methyl propane sulfonic acid 2-hydroxy-3-methacryloyloxy- EXAMPLE 1 22 g. of polyvinyl alcohol were dissolved in 500 cc. of water. The mixture was cooled to room temperature and nitrogen was bubbled through for about 30 minutes. 25 g. (0.25 mole) of ethyl acrylate, 18 g. (0.25 mole) of acrylic acid and 2.15 g. of ethyl dimethyl benzyl ammonium chloride were then added. After'stirring for 15 minutes, 20 cc. of 0.2M Ce(l\l1-1.,) (NO in 1M nitric acid were added and the reaction was continued overnight at room temperature under a blanket of nitrogen to yield the graft polymer of Formula (1).

EXAMPLE 2 11 g. of PVA were dissolved in 500 cc. of water under nitrogen was bubbled through themixture. 25 g. (0.25 mole) of ethyl acrylateQlSg. (0.25 mole) of acrylic acid and 2.15 g. of cetyl dimethyl benzyl ammonium chloride were then addedfAfter stirring for 30 minutes, 20 cc. of 0.2M Ce(Nl-l (NO in 1m nitric acid were then added. The reaction was continued at room temperature overnight to yield the graft copolymer ofFormula (2).

The graft polymers of Formulae (3) through (6) were prepared in the foregoing manner by varying the amounts of reactants. For example, employment of 9 g. of acrylic acidin the procedure of Example 1 yields the polymer of Formula (3); and employment of 44 g. of PVA yields the polymer of Formula (4).

' EXAMPLE 3 To a stirred solution of 22 g. of PVA in 500 cc. of water under nitrogen were added 36 g. of acrylic acid (0.5 mole) and 20 cc. of 0.1M (NH Ce(N0 in 1M nitric acid. Stirring was continued overnight to yield the graft polymer of Formula (7).

EXAMPLE 4 22 g. (0.5 mole) of PVA were dissolved in 500 cc. of water under nitrogen. 25 g. (0.25 mole) of isobutyl vinyl ether and 24.5 g. (0.25 mole) of maleic anhydride were added at room temperature under a blanket of nitrogen. 20 cc. of 0.1M (NH.,) Ce(NO in 1M nitric acid were added and stirring was continued overnight to yield the graft polymer of Formula (8).

EXAMPLE To a stirred solution of 22 g. of PVA- in 500 cc. of water under nitrogen were added 2.15 g. of cetyl dimethyl pyridinium chloride,25 g. (0.29 mole) of vinyl acetate and 9 g. (0.125 mole) of acrylic acid. The pH was adjusted to 1.5 with concentrated nitric acid and 2.2 g. of Ce(NH,,) (NO in 10 cc. of water were then added. Stirring was continued for 2 hours to yield the graft polymer of Formula (9).

Employment of 18 g. of acrylic acid and 1.1 g. of Ce(Nl-1.,) (NO in the above Example yielded the graft polymer of Formula (10).

EXAMPLE 6 To a stirred solution of 22 g. of PVA'in 500 cc. of water under nitrogen were added 2.33 g. of cetyl dimethyl benzyl ammonium chloride,25 g. (0.25 mole) of ethyl acrylate and 21.5 g. (0.25 mole) of methacrylic acid. The temperature was raised to 50C. The pH was adjusted to 1.5 with concentrated nitric acid and 3.3 g. of Ce(NH.,) (NO in 10 cc. of water were then added. Stirring was continued for 2 hours to yield the graft polymer of Formula (11).

EXAMPLE 7 To a solution of 300 g. of an isopropyl acrylamide graft on PVA (14.6% solids, 74.0% by weight isopropyl acrylamide)'in 700 cc. of water were added 25 g. (0.25 mole) of ethyl acrylate and 18 g. (0.25 mole) of acrylic acid. Nitrogen was bubbled through the mixture for one hour and the pH was adjusted to 1.5 with concentrated nitric acid. The temperature was raised to 50C. and 2.2 g. of Ce(NH.,) (N( in 10 cc. of water were then added. Stirring was continued for 2 hours to yield the graft polymer of Formula (12).

EXAMPLE 8 To a stirred solution of 11 g. of PVA in 500'cc.-.of-

water under nitrogen were added 2.15 g. 'of'cetyl trimethyl ammonium bromide, 25 g. (0.29 mole) of methyl acrylate and 5 g. (0.0695 mole) of acrylic acid. Nitrogen was bubbled through the mixture for one hour. The temperature was raised to 50C and the pH was adjustedto 1.5 with concentrated nitric acid. 4.0 g. of Ce(NH,) (NO in 10 cc. of water were then added. Stirring was continued for 2 hours to yield the graft polymer of Formula (13).

Varying the amounts of reagents in the foregoing Example provided the graft polymers of Formulae (14) to.

EXAMPLE 9 To a solution of 44 g. of PVA in 500 cc. of water were added 50 g. of ethyl acrylate, 36 g. of acrylic acid and 5 g. of 2-hydroxy-3-methylacrylyloxypropyltrimethylammonium chloride. Nitrogen was bubbled through the mixture for one hour and the pH was adjusted to 1.5 with concentrated nitric acid. The temperature was raised to 50C and 6.6 g. of Ce(NH,,)-,,('NO;,) in 50 cc. of water were then added. Stirring was continued for 2 hours to yield the graft polymer of Formula (20).

EXAMPLE 10 To a solution of 22 g. of PVA in 500 cc. of water were added 25 g. (0.25 mole) of ethyl acrylate, 5 g. (0.07 mole) of acrylic acid and 10 g. (0.04 mole) of 2- hydroxy-3:methylacrylyloxypropyL trimethylammonium chloride. Nitrogen was bubbled through the mixture for one hour and the pH was adjusted to 1.5 with concentrated nitric acid. The temperature was raised to 50C and 3.3 g. of Ce(NH.,) (NO in 10 cc. of water were then added. Stirring was continued for 2 hours of yield the graft polymer of Formula EXAMPLE 11 To a stirred solution of 22 g. of PVA in 500 cc. of water under nitrogen were added 25 g. (0.29 mole) of methyl acrylate, 36 g. (0.5 mole) of acrylic acid and 5 g. (0.02 mole) of 2-hydroxy-3-methylacrylyloxypropyltrimethylammonium chloride. Nitrogen was bubbled through the mixture for one hour and the pH was adjusted to 1.5 with concentrated nitric acid. The temperature was raised to 50C and 8.0 g. of Ce(NH (NO in 20 cc. of water were then added. Stirring was continued for 2 hours to yield the graft polymer of Formula EXAMPLE 12 To a stirred solution of 22 g. of PVA in 500 cc. of water under nitrogen were added 25 g. (0.29 mole) of methyl acrylate, 36 g. (0.5 mole) of acrylic acid and 10 g. (0.04 mole) of 2-hydroxy-3-methylacrylyloxypropyltrimethylammonium chloride. Nitrogen was bubbled through the mixture for one hour and the pH was adjusted to 1.5 with concentrated nitric acid. The temperature was raised to 50C and 8.0 g. of Ce(NH.,) (NO in 20 cc. of water were then added. Stirring was continued for 2 hours to yield the graft polymer of Formula (23).

EXAMPLE l3 To a solution of l 1 g. of PVA in 400 cc. of water, g. of diacetone acrylamide, 66 'g. of acrylic acid and 40 g. of 5 percent NaSEM were added. Nitrogen was bubbled through themixture for one hourand the temperature was raised to 50C after which 4.4 g. of ceric ammonium nitrate and 0.5 -g. of nitric acid were added. Stirring was continued for 2 hours to yield the graft polymer of Formula (28).

EXAMPLE 14 30 g. of HEC and 4.0 g. of Triton X-l00" (tradename of Rohm & Haas Co. for a nonionic wetting agent, isooctyl phenyl polyethoxy ethanol) were dissolved in 500 cc. of water. 36 g. (0.36 mole) of ethyl acrylate, 54 g. (0.63 mole) of methacrylic acid and 10 g. (0.14 mole) of acrylic acid were added. Nitrogen was bubbled through the mixture for one hour, after which the temperature was raised to 50C and 8.0 g. of Ce(NH (NO in 20 cc. of water were added. Stirring was continued for 2 hours to yield the graft polymer of Formula (29).

Substitution of 15 g. of acrylic acid in the above EX- ample yielded the polymer of Formula (30).

EXAMPLE 15 To a solution of 30 g. of HEC in 500 cc. of water were added 4.0 g. of Triton X-lOO, 36 g. of ethyl acrylate and 54 g. of methacrylic acid. The temperature was raised to 50C and nitrogen was bubbled through 'for one hour, after which 8.0 g. of Ce(Nl-1.,) (NO in cc. of water were added. Stirring for 2 hours yielded the graft polymer ofFormula (31 EXAMPLE 1-6 To a solution of 30 g. of HEC in 500 cc. of water were added 4 g. ofTriton X-100, 36 g. of methyl acrylate and 54 g. of methacylic acid. Nitrogen was bubbled through for one hour and the temperature was raised to 70C, after which 8 g. of Ce(Nl-l.,) (l\lO in 20 cc. of water were added. Stirring for 2 hours yielded the graft polymer of Formula (33). v

Substitution of 70 g. of methacrylic acid in the above I Example yielded the graft polymer of Formula (34).

EXAMPLE '17 v To a solution of 20 g. of HEC in 500 cc. of water were added g. of methyl acrylate and 36 g. of acrylic acid. Nitrogen was bubbled through for one hour and the temperature was raised to 70C, after which 8 g. of Ce(NH (NO in cc. of water were added. Stirring for 2 hours yielded the graft polymer of Formula EXAMPLE 1 8 To a solution of 30 g. of BBC in 500 cc. of'water were added 4 g. of Triton X-lOO, 28 g. of methyl acrylate, 8 g. of ethyl acrylate and 54 g. of methacrylic acid. Nitrogen was bubbled through for one hour and the temperature was raised to 70C, after which 8 g. of

Ce(I Il-l.;) (NO in 20 cc. of water were added.-Stirring for 2 hours yielded the graft polymer of Formula (38).

EXAMPLE 19 To a solution of 30 got BBC in 500cc. of water were added 4 g. ofTriton X-lOO, 36 g. of ethyl acrylate,.54 g. of methacrylic acid and 5 g. of diacetone acrylamide. Nitrogen was bubbled through for one hour and the temperature was raised to C, after which 8 v g. of Ce(NH (N0 in 20 cc. of water were added. Stirring for 2 hours yielded the graft polymer of Formula (40).

EXAMPLE 20 EXAMPLE 21 To a solution of 60 g. of soluble starch in 500 cc. of water were added 4 g. of Triton X-lOO, 72 g. of

methyl acrylate and 108 g. of methacrylic acid. Nitrogen was bubbled through for one hour. The temperature was raised to C and 8 g. of ceric ammonium nitrate in 20 cc. of water were added. Stirring for 2 hours yielded the graft polymer of Formula (48).

EXAMPLE 22 To a solution of g. of soluble starch in 850 cc. of water were added 5 g. of 2-sulfoethyl methacrylate,

62.5 gsof ethyl acrylate'and 115 g. ofacrylic acid. Ni-

trogen was bubbled through for one hour and the temperature was raised to 70C, after which 12.5 g. of Ce(NH (NO in 50 cc. of water were added. Stirring was continued for 2 hours to yield the graft polytiter of Formula (49).

' EXAMPLE 23 To a solution of 60 g. of soluble starch in 500 cc. of water were added 72 g. of methyl acrylate, 108g. of acrylic acid and 2 g. of sulfoethyl methacrylate. Nitrogen was bubbled through for one hour and the temperature was raised to 70C, after which 8 g. of

Ce(Nl-l,,) (NO in 30 cc. of water were added. Stirring was continuedfor 2 hours and 200 cc. of water were then added to yield the graft polymer of Formula (51).

EXAMPLE 24 To a solution of 60 g. of soluble starch in 300 cc. of water were added 40 g. of a 5 percent solution of sodium 2-sulfoethyl methacrylate, 72 g. of methyl acrylate and 108 g. of methacrylic acid. Nitrogen was bubbled through the mixture for one hour and 16 g. of Ce(Nl-I (NO in 40 cc. of water were then added. Stirring was continued for 3 1/2 hours to yield the graft polymer of-Formula (52). i

7 EXAMPLE 25 Example 25 was modified, employing 72 g. of ethyl acrylate instead of 72 g. of methyl acrylate and 30 g. of 5 percent sodium-2-sulfoethyl methacrylate instead of 40 g. to yield the graft polymer of Formula (53).

EXAMPLE 26 Example 25 was repeated, adding 2.75 g. of methylolated diacetone vacrylamide to the monomers employed, to yield the' graft polymer of Formula (54).

EXAMPLE 27 To a solution of 200 g. of ethylenelmaleic acid copolymer in one liter of water were added 4 g. of 2-acrylamido-2-methyl-propane sulfonic acid and 80 g. of methyl acrylate. Nitrogen was bubbled through for one hour, the temperature was raised to 60C and 1.1 gpof ceric ammonium nitrate was then added. Stirring was continued for hours to yield the graft polymer of Formula (57).

' EXAMPLE 2s Substitution of diacetone acrylamide for methyl acrylate in the above Example yielded the graft polymer of Formula (58).

EXAMPLE 29 To a solution of 167 g. of ethylene/maleic acid copolymer in 950 cc. of water were added g. of diacetone acrylamide, 4 g. of 2-acrylamido-2-methylpropane sulfonic acid and g. of 2-hydroxy-3-methacryloyloxypropyl trimethyl ammonium chloride. Nitrogen was bubbled through for one hour, the temperature was raised to 60C and a solution of 50 cc. of water, 5 g. of nitric acid and 5.5 g. of ceric ammonium nitrate were then added. Stirring for 2 hours then yielded the graft polymer of Formula (59).

EXAMPLE 30 Employment of 80 g. of diacetone acrylamide (instead of 130 g.) plus 50 g. of butyl acrylate in the procedure of the above Example yielded the graft polymer 'of Formula (60).

EXAMPLE 31 Substitution of butyl acrylate for methyl acrylate in the procedure of Example 28 yielded the graft polymer of Formula (61). 1

As was heretofore mentioned, the neutralizing layer of this invention isuseful in systems wherein the photosensitive strata and the dyeable stratum are contained on separate elements; and in systems wherein they are contained together as a unitary film unit, e.g., in the integral negative-positive film units previously described. In the former type, the neutralizing layer is most preferably contained in association with the dyeable stratum, e.g., in an image-receiving element comprising a support carrying the neutralizing layer and the dyeable stratum, a spacer or timing layer preferably being disposed therebetween. It may however be contained as a layer in the photosensitive element, i.e., in the element containing the photosensitive strata, as is disclosed in U. S. Pat. No. 3,362,821. In like manner, in the integral negative-positive film units, the neutralizing layer is preferably associated with the dyeable stratum, e.g., on the side of the dyeable stratum opposed from the negative component, and most preferably a timing layer is disposed between the neutralizing layer and dyeable stratum.

As will be discussed in more detail hereinafter, the present invention is particularly useful in those film units, such as the heretofore described integral negative-positive film units, wherein the negative and positive components are at least retained together following image formation as the final print. The invention will accordingly be illustrated by reference to atypical film unit of this description.

As shown in the drawing, such a film unit may comprise, as the essential layers, a layer l3 of cyan dye developer, red-sensitive silver halide emulsion layer 14, interlayer 15, a layerof magenta dye developer 16,

green-sensitive silver halide emulsion layer 17, interlayer 18, yellow dye developer layer 19, blue-sensitive silver halide emulsion layer 20, auxiliary layer 21,

image receiving layer or dyeable stratum 22, spacer layer 23, and a pH-reducing or neutralizing layer 24. Layers 13-21 comprise the negative component and layers 22-24 comprise the positive component. These may possess a processing composition solvent vapor permeably sufficient to effect, subsequent to substan tial transfer image formation and prior to any substantial environmental image degradation to which the resulting image may be prone, osmotic transpiration of processing composition solvent in a quantity effective to decrease the solvent from a first concentration at which the color-providing material is diffusible to a second concentration at which it is not. Although these layers may possess a vapor transmission rate of l or less gms./24 hr./l00 in. /mil., they preferably possess a vapor transmission rate for the processing composition solvent averaging not less than about gms./24 hr.s/ hrs./100 in. /mil., most preferably in terms of the preferred solvent, water, a vapor transmission rate averaging in excess of about 300 grns. of water/24 hrs./l00 in. /mil., and may advantageously comprise a microporous polymeric film possessing a pore distribution which does not unduly interfere with the dimensional stability of the layers or, where required, the optical characteristics of such layers. As examples of useful materials of this nature, mention may be made of those having the aforementioned characteristics and which are derived from ethylene glycol terephthalic acid; vinyl chloride polymers;'polyvinyl acetate; cellulose derivatives, etc. As heretofore noted layer 12 is of sufficient opacity to prevent fogging from occurring by light passing therethrough, and layer 26 is transparent to permit photoexposure and for viewing of a transfer image formed on' receiving layer 23.

The silver halide layers preferably comprise photosensitive silver halide, e.g., silver chloride, bromide or iodide or mixed silver halides such as silver iodobromide or chloriodobromide dispersed in a suitable colloidal binder such as gelatin and such layers may typically be on the order of 0.6 to 6 microns in thickness. It will be appreciated that the silver halide layers may and in fact generally do contain other adjuncts, e.g., chemical sensitizers such as are disclosed in U. S. Pat. Nos. 1,574,944; 1,623,499; 2,410,689; 2,597,856; 2,597,915; 2,487,850; 2,518,698; 2,521,926; etc.', as well as other additives performing specific desired functions, e.g., coating aids, hardeners, viscosityincreasing agents, stabilizers, preservatives, ultraviolet absorbers and/or speed-increasing compounds. While the preferred binder for the silver halide is gelatin, others such as albumin, casein, zein, resins such as cellulose derivatives, polyacrylamides, vinyl polymers, etc., may replace the gelatin in whole or in part.

The respective dye developers, which may be any of I those heretofore known in the art and disclosed for example in U. S. Pat. No. 2,983,606, etc., are preferably dispersed in an aqueous alkaline permeable polymeric binder, e.g., gelatin as a layer from about 1 to 7 microns in thickness.

Interlayers l5, l8 and 21 may comprise an alkaline permeable polymeric material such as gelatin and may be on the order of from about 1 to 5 microns in thickness. As examples of other materials for forming these interlayers, mention may be made of those disclosed in U. S. Pat. Nos. 3,421,892, 3,575,701, 3,615,422 and 3,625,685. These interlayers may also contain additional reagents performing specific functions and the various ingredients necessary for development may also be contained initially in such layers in lieu of being present initially in the processing composition, in which event the desired developing composition is obtained by contacting such layers with the solvent for forming the processing composition, which solvent may include the other necessary ingredients dissolved therein.

The image-receiving layer may be on the order of 0.25 to 0.4 mil. in thickness. Typical materials heretofore employed for this layer include dyeable polymers such as nylon, e.g., N-methoxymethyl polyhexamethylene adipamide; partially hydrolyzed polyvinyl acetate; polyvinyl alcohol with or without plasticizers; cellulose acetate with filler as, for example, onehalf cellulose acetate and one-half oleic acid; gelatin; polyvinyl alcohol'or gelatin containing a dye mordant such as poly-4-vinylpyridine, etc. Such receiving layers may, if desired, contain suitable mordants, e.g., any of the conventional mordant materials for acid dyes such as those disclosed, for example, in the aforementioned U. S. Pat. No. 3,227,5 50; as well as other additives such as ultraviolet absorbers, pH-reducing substances, etc. It may also contain specific reagents performing desired functions, e.g., a development restrainer, as disclosed,

for example, in U. S. Pat. No. 3,265,498.

The spacer or timing layer may be on the order of 0.1 to 0.7 mil thick. Materials heretofore used for this pur pose include polymers which exhibit inverse temperature-dependent permeability to alkali, e.g., as disclosed in U. S. Pat. No. 3,445,686. Materials previously employed for this layer include polyvinyl alcohol, cyano= ethylated polyvinyl alcohol, hydroxypropyl polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyvinyl oxazolidinone, hyroxypropyl methyl cellulose, partial acetals of polyvinyl alcohol such as partial polyvinyl butyral and partial polyvinyl propional, polyvinyl amides such as polyacrylamide, etc.

The neutralizing layer may be on the order of 0.3 to 1.5 mil. in thickness. In accordance with this invention, it will include one of the aforementioned graft polymers, most preferably contained at a coverage of less than 3000 mgs./ ft.

As was mentioned previously, the neutralizing layers of this invention may be coated as aqueous emulsions.

have heretofore been coated from an aqueous medium,-

e.g., the water-soluble polymeric acids described and claimed in the aforementioned Schlein et al. application Ser. No. 165,171.

With the use of such hydrophilic acids, there is the. inherent problem of water from the processing fluid piling up at the neutralizing layer and/or at the interface of the neutralizing layer and the timing layer. This pil ing up of water in turn causes certain distinct problems,

chief of which is the tendency for delamination to occur, which separation renders the final print objectionable. While this problem is most pronounced in those film units wherein the negative and positive components together retained together so that the processing fluid remains confined therebetween, e.g., in the heretofore described integral film units, it is also a problem, although to a lesser extent, in those systems wherein the respective negative and'positive components are retained on separate elements which are separated following image formation.

Since the neutralizing layers of this invention adhere extremely well at both interfaces in the laminar structure, they resist any tendency for delamination to occu subsequent to transfer image formation.

By way of further illustrating the practice of this invention and the types of film units to which it is directed, an integral negative-positive film unit of the type described and claimed in U. S. Pat. No. 3,415,644 and shown in the illustrative drawing may be prepared, for example, by coating, in succession, on a gelatin subbed, 4 mil. opaque polyethylene terephthalate film base, the following layers:

1. a layer of cyan dye developer dispersed in gelatin and coated at a coverage of about 100 mgs./ft. of dye and about mgslft. of gelatin;

2. a red-sensitive gelatino silver iodobromide emulsion coated at a coverage of about 140 mgsJft. of silver and about 70 mgs./ft. of gelatin;

3. a layer of a 60-30-4-6 copolymer of butylacrylate,

'diacetone, acrylamide, styrene and methacrylic .acid

and polyacrylamide coated at a coverage of about 150 mgs./ft. of the copolymer and about 5 mgs./ft. of polyacrylamide;

.4. a layer of magneta dye developer dispersed in gelatin and coated at a coverage of about mgs./ft. of dye and about 100 mgsJft. of gelatin;

5. a green-sensitive gelatino silver iodobromide emulsion coated at a coverage of about 100 mgs./ft. of silver and about 50 mgs./ft. of gelatin; 1

6. a layer containing the copolymer referred to above in layer 3 and polyacrylamide coated coverage a coveraege of about 100 mgs./ft. of copolymer and about 12 mgs./ft. of polyacrylamide;

7. a-layer of yellow dye developer dispersed in gelatin and coatedat a coverage of about 70 mgs./ft.'*' of dye and about 56 mgs./ft. of gelatin;

8. a blue-sensitive gelatino silver iodobromide emulsion layer including the auxiliary developer 4'- .methylphenyl hydroquinone coated at a coverage of about mgs./ft-. of silver, about 60 mgs./ft. of gelatin and about 30 mgs./ft. of auxiliary developer; and

9. a layer of gelatin coated at a coverage of about 50 mgs./ft. of gelatin.

The three dye developers employed above may be the following:

a cyan dye developer;

BIO-CHr-Ulia N-SO N=N -'|CHa was j t XII/Hi N 0 0 0B. gfl-CE-CH a magenta dye developer; and

OCaH1 NO;

gleam a yellow dye developer.

Then a transparent 4 mil. polyethylene terephthalate film base may be coated, in succession, with the following illustrative layers:

1. a neutralizing layer comprising the graft polyme of Formula (28) coated at a coverage of about 2,400

2. a graft copolymer of acrylamide and diaceto ne acrylamide on a polyvinylalcohol backbone ina molar ratio of 1:3.2z1 at a coverage of about 700 mgs./ft., to provide a polymeric spacer or timing layerjand 3. a 2:1 mixture, by weight, of polyvinyl alcohol and poly-4-vinylpyridine, at a coverage of about 400 mgsJft. and including about 20 mgs./ft. of a development restrainer, l-phenyl-5-mercaptotetrazole, to pro-j vide a polymeric image-receiving layer containing development restrainer. v

The two components may then be laminated together to provide the desired integral film unit.

A rupturable container comprising an outer layer of lead foil and an inner liner or layer or polyvinyl chloride retaining an aqueous alkaline processing solution may then be fixedly mounted on the leading edge of each of the laminates, by pressure-sensitive tapes, in-

terconnecting the respective container and laminates so that, upon application of compressive pressure to the container to rupture the containers marginal seal, its contents may be distributed between the dyeable stratum (layer 3 of the positive component) and the gelatin layer (layer 9) of the negative component.

An illustrative processing composition to be employed in the rupturable container may comprise the following properties of ingredients:

Water cc. Potassium hydroxide 11.2 gins. Hydroxyethyl cellulose (high viscosity) [commercially aveil- 3.4 gms.

able from Herclues Powder 00., Wilmington, Delaware, under the trade name Natrasol 250].

i l-CH3 CHi N- C Has-n r- 121125- E i-CH5 This film unit may then be exposed in known manner to form a developable image and the thus exposed element may then be developed by applying compressive pressure to the rupturable container in order to distribute the aqueous I alkaline processing composition, thereby forming a multicolor transfer image which is viewable through the transparent polyethylene terephthalate film base as a positive reflection print.

As was mentioned earlier the neutralizing layers of 1.1a gms.

. 23 this invention have been found to adhere extremely well, thereby obviating any tendency for delamination to occur. In order to illustrate this point further a typical neutralizing layer heretofore known in the art has a tensile strength on the order of 80 grams peal force/inch or less. As distinguished from these prior neutralizing layers, the peal force/inch of the neutralizing layer prepared in the foregoing illustrative example is so great as to be immeasurable.

Since certain changes may be made in the above product and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above desciptio'n shall be interpreted as illustrative and not in -a limiting sense.

What is claimed is:

1. In a photographic product comprising a photosensitive element including at least one light-sensitive silver halide layer having a dye image-providing material associated therewith or an image-receiving element including a stratum adapted for receiving an image by diffusion transfer, said photographic product including a neutralizing layer for lowering the environmental pH subsequent to application of an aqueous alkaline processing composition;

the improvement wherein said neutralizing layer comprises a graft copolymer comprising the residue of a graftable polymer providing-an acid moiety grafted onto a polymeric backbone.

2. A photosensitive element including at least one light-sensitive silver. halide layer having a dye imageproviding material associated therewith and a neutralizing layer comprising a graft copolymer comprising the residue of a graftable polymer providing an acid moiety grafted onto a polymeric backbone.

3. A photosensitive element as defined in claim 2 including a dyeable stratum adapted for forming a color image by diffusion transfer. 7 v

4. A process for forming a visible image in color comprising the steps of exposing a photosensitive element as defined in claim 3 to form a developable image and thereafter applying an aqueous alkaline processing composition to said exposed element to form said color image.

5. A'photosensitive element as defined in claim 3 wherein said dyeable stratum is disposed between said silver halide strata and associated dye image-providing material and said neutralizing layer.

6. In an integral negative-positive film unit including a negative component comprising at least one light sensitive silver halide emulsion layer having a dye'i mage-providing material associated therewith, a positive component including at least a dyeable stratum, means for applying a reflecting layer between said positive and negative components in an amount sufficient upon development of said film unit to mask effectively said negative component and to provide a background for viewing a color image imparted to said dyeable stratum of said positive component by reflected light by applying an aqueous alkaline processing fluid to said film unit after exposure thereof, said film unit further including a neutralizing layer for lowering the environment pH subsequent to application of said alkaline processing fluid; v

the improvement wherein said neutralizing layer comprises a. graft copolymer comprising the residue of a graftable polymer providing an acid moiety grafted onto a polymeric backbone.

7. A process for forming a color transfer image-comprising the steps of exposing a film unit as defined in claim 6 to form a developable image and thereafter applying an aqueous alkaline processing composition to develop said image and to form, as a function of development, an imagewise distribution of dye imageproviding material which is transferred, at least in part, by diffusion, to said dyeable stratum to impart thereto a color transfer image viewable, without separation, by reflected light as a positive color reflection print.

8. A film unit as defined in claim 6 wherein said neutralizing layer is disposed on the side of said dyeable stratum opposed from said negative component.

9. A film unit as defined in claim 8 wherein a timing layer is disposed between said dyeable stratum and said neturalizing layer.

10. A film unit as defined in claim 8 wherein said negative component includes a red-sensitive silver halide emulsion having a cyan dye image-providing material associated therewith, a green-sensitive silver halide emulsion having a magenta dye image-providing material associated therewith and a blue-sensitive silver halide emulsion having a yellow dye image-providing material associated therewith.

11. A film unit as defined in claim 10 wherein said dye image-providing materials are initially soluble or diffusible in said aqueous alkaline processing fluid but are selectively rendered non-diffusible in an imagewise pattern as a function of development.

l 12. A fllm unit as defined in claim 6 including means for applying said aqueous alkaline processing fluid to develop said film unit.

i '13; A film unit as defined in claim 6 wherein said negative and positive components are confined between a pair of support members, at least the support member associated with the positive component being transparent.

14. A film unit as defined in claim 6 wherein said positive and negative components are confined on a transparent support member associated with said positive component.

is. A film unit as defined in claim 6 wherein said means for applying a reflecting layer comprises a layer of a white pigment disposed ina layer between said positive and negative components.

16. A film unit as defined in claim 6 wherein said means for applying a reflecting layer comprises a white pigment dispersed in said processing fluid.

l7.'A photosensitive element including a composite structure containing,las essential layers, in sequence, a dimensionally stable alkaline solution impermeable opaque layer, a layer containing a cyan dye developer, a red-sensitive gelatino silver halide emulsion layer, a layer containing a magenta dye developer, a greensensitive gelatino silver halide emulsion layer, a layer containing a yellow dye developer, a blue-sensitive gelatino silver halide emulsion layer, a dyeable stratum, a neutralizing layer comprising a graft copolymer comprising the residue of a graftable polymer providing an acid moiety grafted onto a polymeric backbone in an amount sufficient to effect reduction of a processing solution having a first pH at which said dye developers are soluble and diffusible to a second pH at which said dye developers are substantially insoluble and nondiffusible, a dimensionally stable alkaline solution impermeable transparent layer, means securing at' least the side edges of said opposed layersin fixed relationship, and a rupturable container retaining an aqueous alkaline processing solution having said first pH and containing dispersed therein a white inorganic pigment in a quantity sufficient to' mask effectively said silver halide layers and any dye developer associated therewith after development and to provide a background for viewing a diffusion transfer image formed by development of said film unit, by reflected light, through said transparent layer, said rupturable container being fixedly positioned and extending transverse a leading edge of said photosensitive element so as to be capable of effecting unidirectional discharge of the containers contents between said dyeable stratum and said third spacer layer upon application of compressive force to said neutralizing layer. 

2. A photosensitive element including at least one light-sensitive silver halide layer having a dye image-providing material associated therewith and a neutralizing layer comprising a graft copolymer comprising the residue of a graftable polymer providing an acid moiety grafted onto a polymeric backbone.
 3. A photosensitive element as defined in claim 2 including a dyeable stratum adapted for forming a color image by diffusion transfer.
 4. A process for forming a visible image in color comprising the steps of exposing a photosensitive element as defined in claim 3 to form a developable image and thereafter applying an aqueous alkaline processing composition to said exposed element to form said color image.
 5. A photosensitive element as defined in claim 3 wherein said dyeable stratum is disposed between said silver halide strata and associated dye image-providing material and said neutralizing layer.
 6. In an integral negative-positive film unit including a negative componeNt comprising at least one light-sensitive silver halide emulsion layer having a dye image-providing material associated therewith, a positive component including at least a dyeable stratum, means for applying a reflecting layer between said positive and negative components in an amount sufficient upon development of said film unit to mask effectively said negative component and to provide a background for viewing a color image imparted to said dyeable stratum of said positive component by reflected light by applying an aqueous alkaline processing fluid to said film unit after exposure thereof, said film unit further including a neutralizing layer for lowering the environmental pH subsequent to application of said alkaline processing fluid; the improvement wherein said neutralizing layer comprises a graft copolymer comprising the residue of a graftable polymer providing an acid moiety grafted onto a polymeric backbone.
 7. A process for forming a color transfer image comprising the steps of exposing a film unit as defined in claim 6 to form a developable image and thereafter applying an aqueous alkaline processing composition to develop said image and to form, as a function of development, an imagewise distribution of dye image-providing material which is transferred, at least in part, by diffusion, to said dyeable stratum to impart thereto a color transfer image viewable, without separation, by reflected light as a positive color reflection print.
 8. A film unit as defined in claim 6 wherein said neutralizing layer is disposed on the side of said dyeable stratum opposed from said negative component.
 9. A film unit as defined in claim 8 wherein a timing layer is disposed between said dyeable stratum and said neturalizing layer.
 10. A film unit as defined in claim 8 wherein said negative component includes a red-sensitive silver halide emulsion having a cyan dye image-providing material associated therewith, a green-sensitive silver halide emulsion having a magenta dye image-providing material associated therewith and a blue-sensitive silver halide emulsion having a yellow dye image-providing material associated therewith.
 11. A film unit as defined in claim 10 wherein said dye image-providing materials are initially soluble or diffusible in said aqueous alkaline processing fluid but are selectively rendered non-diffusible in an imagewise pattern as a function of development.
 12. A film unit as defined in claim 6 including means for applying said aqueous alkaline processing fluid to develop said film unit.
 13. A film unit as defined in claim 6 wherein said negative and positive components are confined between a pair of support members, at least the support member associated with the positive component being transparent.
 14. A film unit as defined in claim 6 wherein said positive and negative components are confined on a transparent support member associated with said positive component.
 15. A film unit as defined in claim 6 wherein said means for applying a reflecting layer comprises a layer of a white pigment disposed in a layer between said positive and negative components.
 16. A film unit as defined in claim 6 wherein said means for applying a reflecting layer comprises a white pigment dispersed in said processing fluid.
 17. A photosensitive element including a composite structure containing, as essential layers, in sequence, a dimensionally stable alkaline solution impermeable opaque layer, a layer containing a cyan dye developer, a red-sensitive gelatino silver halide emulsion layer, a layer containing a magenta dye developer, a green-sensitive gelatino silver halide emulsion layer, a layer containing a yellow dye developer, a blue-sensitive gelatino silver halide emulsion layer, a dyeable stratum, a neutralizing layer comprising a graft copolymer comprising the residue of a graftable polymer providing an acid moiety grafted onto a polymeric backbone in an amount sufficient to effect reduction of a processing solution having a first pH at which said dye developers are soluble and diffusible to a second pH at which said dye developers are substantially insoluble and non-diffusible, a dimensionally stable alkaline solution impermeable transparent layer, means securing at least the side edges of said opposed layers in fixed relationship, and a rupturable container retaining an aqueous alkaline processing solution having said first pH and containing dispersed therein a white inorganic pigment in a quantity sufficient to mask effectively said silver halide layers and any dye developer associated therewith after development and to provide a background for viewing a diffusion transfer image formed by development of said film unit, by reflected light, through said transparent layer, said rupturable container being fixedly positioned and extending transverse a leading edge of said photosensitive element so as to be capable of effecting unidirectional discharge of the container''s contents between said dyeable stratum and said third spacer layer upon application of compressive force to said container.
 18. A film unit as defined in claim 17 wherein said cyan dye developer is a phthalocyanine dye developer; said magenta dye developer is a 1:1 chrome-complexed azo dye developer; and said yellow dye developer is a 1:1 chrome-complexed azomethine dye developer.
 19. A film unit as defined in claim 18 including a timing layer disposed between said dyeable stratum and said neutralizing layer. 